| 锦屏深部地下实验室初始地应力测量实践 |
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| 引用本文： | 钟山,江权,冯夏庭,刘继光,李邵军,邱士利,吴世勇.锦屏深部地下实验室初始地应力测量实践[J].岩土力学,2018,39(1):356-366. |
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| 作者姓名： | 钟山 江权 冯夏庭 刘继光 李邵军 邱士利 吴世勇 |
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| 作者单位： | 1. 中国科学院武汉岩土力学研究所，岩土力学与国家重点实验室，湖北 武汉 430071；2. 中国科学院大学，北京 100049； 3. 雅砻江流域水电开发有限公司，四川 成都 610051 |
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| 基金项目： | 国家重点研发计划(No. 2016YFC0600707)；国家自然科学基金(No. 51379202，No. 51309218)。 |
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| 摘 要： | 地应力条件是大型地下洞室稳定性分析与工程设计的必要信息之一，对于深部高应力地下工程的安全评价与灾害防治尤为重要。以埋深2 400 m的中国锦屏地下实验室为例，首先重点阐述了高应力下条件下应力解除法测量地应力的原理与方法，并提出了针对在高应力条件下使用36-2型钻孔变形计地应力测量的改进技术：（1）采用新式阶梯状钻头，分级逐步解除，减小岩芯根部应力集中区域的范围和应力大小；（2）使用大直径解除钻头来增加套孔空心圆柱状岩芯的厚度，即增大裂隙贯通整个岩芯的时间；（3）在测点附近钻取勘探孔以获知测点岩体完整性条件，对是否适合开展测试进行评估。在此基础上，通过现场岩体地应力测试获得每个测孔不同深度垂直钻孔轴线平面上的平面应力状态以及三孔交汇处的三维应力状态（3个主应力的大小和方向），分析开挖扰动导致的围岩应力重分布规律与原始应力场分布。依据洞室围岩重分布应力特征与现场实际破坏的空间位置对应关系，结合现场破坏情况和工程区域地质条件，多角度验证了三维应力结果是可靠的，可为进一步的工程稳定性评价以及围岩支护设计提供依据。
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| 关 键 词： | 地应力测量 套孔应力解除法 地下实验室 高应力 岩芯饼化 |
| 收稿时间： | 2017-03-01 |
A case of in-situ stress measurement in Chinese Jinping underground laboratory |
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| ZHONG Shan,JIANG Quan,FENG Xia-ting,LIU Ji-guang.A case of in-situ stress measurement in Chinese Jinping underground laboratory[J].Rock and Soil Mechanics,2018,39(1):356-366. |
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| Authors: | ZHONG Shan JIANG Quan FENG Xia-ting LIU Ji-guang |
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| Institution: | 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China; 2. University of Chinese Academy of sciences, Beijing 100049, China; 3. Yalong River Hydropower Development Company, Ltd., Chengdu, Sichuan 610051, China |
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| Abstract: | In-situ stress condition is one of the essential information of stability analysis and engineering design for underground caverns, and it is particularly important for safety assessment of underground engineering in deep and high-stress condition as well as disaster prevention. Taking Jinping underground laboratory in China (CJPL) buried at a depth of 2 400 m as an example, the principle and method of in-situ stress measurement under high stress based on overcoring method have been expounded at first. Furthermore, some technological improvements are given: 1) Adopting new drill and overcoring gradually to reduce the extent and scope of stress concentration at the roots of the cores; 2) Using large diameter drill to increase the thickness of the hollow cylindrical core, namely increasing the time that fracture needs to cause the rock core to break; 3) Drilling exploration hole near the measuring points to get the integrity condition and to evaluate the feasibility of the test. After theoretical explanation, plane stress state, perpendicular to borehole axis with different depths and three-dimensional stress state are given to analyze original stress field and stress redistribution led by excavation. Verified by the relationship between stress distribution and damage of surrounding rock as well as the result of numerical calculation, the result of three-dimensional stress is proven to be reliable and can be used as a basis of further scientific analysis, engineering stability evaluation and design of disaster prevention. |
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| Keywords: | in-situ stress measurement overcoring method underground laboratory high stress rock core disking |
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